Moisture curable sealer compositions are useful in a variety of applications where a waterproof seal is needed to prevent water from entering a joint or space between adjacent structural members. Examples of such applications include seals between roofing materials and parapet walls, highway and airport runway expansion joints, etc. Moisture curable sealer compositions can also be used for automotive body sealing and undercoating. Such compositions have also been employed for waterproofing various structures, such as concrete structures, and in a mastic or putty form for use in caulking and adhesive applications.
In most cases, it is desirable to rapidly achieve a deep and complete cure. This usually reduces the possibility of forming defects, such as cracks, in the cured composition or seal. In many cases, a rapid cure is also desired to expedite subsequent construction or fabrication operations which cannot be performed until the sealer composition has cured.
Various polymeric materials, especially polyurethanes, have been used extensively as coatings and sealants in construction, automotive, and other applications. However, a disadvantage with polyurethanes, silicones and other conventional moisture curing polymeric coatings and sealer compositions is that they cure slowly under ambient conditions and in cool weather. Polyurethanes and silicones require extensive exposure to atmospheric moisture and when installed between impermeable substrates cure poorly or not at all.
Due to their low cost, and inherent water resistance, bituminous materials have traditionally been used as a main component of roof coatings, foundation coatings, paving, joint sealants, paints, and other end uses. However, existing unreinforced bituminous materials tend to melt, flow, or crack during normal seasonal thermal expansion and contraction.
In the past, there have been several attempts to combine bituminous material with synthetic polymeric materials such as polyurethanes to make moisture curing compounds. However, these previous attempts have not been completely successful. In particular, the known combinations of synthetic polymeric materials and bituminous materials have not produced desirable synergistic qualities such as fast or deep cure. Coal tar has also been modified with urethanes and other synthetic polymers with similar limitations.